What is the maximum email attachment size?

Limits vary by provider: Gmail allows up to 25 MB, Outlook up to 20 MB, and Yahoo Mail up to 25 MB. Many corporate email servers have stricter limits of 10 MB or less.

Which setting should I use for emailing a PDF?

Start with Medium. It renders each page at 86 dpi with 70% JPEG quality, which keeps normal-sized text readable, and the tool shows the new size before you download. For very large PDFs or strict size limits, try the Low setting.

Will the compressed PDF look different to the recipient?

Lossless compression leaves the pages as they are. Medium and Low turn each page into an image at 86 or 65 dpi, so text is no longer selectable and looks softer when zoomed in; small print and fine detail show it most. Open the result before you send it.

Can I use this for scanned documents?

Yes. A scan stores each page as an image, often at a higher resolution than the 86 or 65 dpi that Medium and Low re-render at, so scans often shrink a lot. The tool shows the exact result before you download.

What if the PDF is still too big for my email provider?

Try Low, or send the document in parts: split it into two PDFs with the split PDF tool and compress each one. The tool shows the compressed size before you download, so you can compare it with your provider's limit.

Compress PDF for Email

Most email providers limit attachments to 10–25 MB. If your PDF is too large to send, use the Medium quality setting for a significant size reduction while keeping the document legible. All processing happens locally in your browser.

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How it works

For an attachment, Medium quality is a good first try. pdfjs-dist renders each page to a Canvas at 86 dpi, the canvas is exported as a JPEG at 70% quality, and pdf-lib rebuilds the document with those images. The tool shows the new size before you download, so you can check it against your mail provider's attachment limit. Lossless mode is also available when you want the original text layer preserved.

Processing runs in your browser

Compression runs in your browser tab. pdf-lib and PDF.js shrink the PDF inside the page, and the result lands in your downloads ready to attach. You can check this yourself in your browser's DevTools Network tab.

Related operations

To stitch multiple PDFs into one before compressing, try merge PDF. For pulling out a subset of pages, use split PDF. To extract pages as standalone images, see PDF to image.

Frequently asked questions

What is the maximum email attachment size?: Limits vary by provider: Gmail allows up to 25 MB, Outlook up to 20 MB, and Yahoo Mail up to 25 MB. Many corporate email servers have stricter limits of 10 MB or less.
Which setting should I use for emailing a PDF?: Start with Medium. It renders each page at 86 dpi with 70% JPEG quality, which keeps normal-sized text readable, and the tool shows the new size before you download. For very large PDFs or strict size limits, try the Low setting.
Will the compressed PDF look different to the recipient?: Lossless compression leaves the pages as they are. Medium and Low turn each page into an image at 86 or 65 dpi, so text is no longer selectable and looks softer when zoomed in; small print and fine detail show it most. Open the result before you send it.
Can I use this for scanned documents?: Yes. A scan stores each page as an image, often at a higher resolution than the 86 or 65 dpi that Medium and Low re-render at, so scans often shrink a lot. The tool shows the exact result before you download.
What if the PDF is still too big for my email provider?: Try Low, or send the document in parts: split it into two PDFs with the split PDF tool and compress each one. The tool shows the compressed size before you download, so you can compare it with your provider's limit.

Last reviewed September 30, 2026

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